Disinfection of areas of medical facilities is a key component to reduce or eliminate hospital acquired infections, also known in the art as nosocomial diseases or infections. The problem has become so serious that many medical facilities close or restrict areas to allow for intensive methods to eradicate the micro-organisms that cause these infections.
Ultraviolet radiation and more recently high intensity narrow spectrum (HINS) light have been found to be ways to treat these areas to reduce the levels of these micro-organisms. Ultraviolet germicidal irradiation is a disinfection method that uses ultraviolet radiation at a sufficiently short wavelength to break down these micro-organisms. Ultraviolet-C radiation with a wavelength of between 180-280 nm (and particularly between 240 nm-280 nm) has been found to be particularly effective. UV-B between 280-320 nm also has germicidal properties. The relatively short wavelengths of ultraviolet-C and B radiation are harmful to forms of life at the micro-organic level by destroying the ability of microorganisms to reproduce by causing photochemical changes in nucleic acids in these organisms so that their DNA and/or RNA chemical structure is disrupted. The disruption prevents micro-organisms from replicating, thereby rendering them inactive and unable to cause infection.
Disinfecting using ultraviolet radiation has been limited. This is mainly due to existing systems being configured to require the treated areas to be unoccupied by people. This precaution stems from the fact that UV exposure to unprotected skin can produce various negative effects including erythema, photosensitivity, skin aging, immune system damage, and even increased occurrences of skin cancer. The most serious effects of UV exposure are those which affect the eyes, the results of which can produce photokeratitis and conjunctivitis and other corneal injuries, including potentially cataracts in the eye lens. It so happens that wave lengths most effective for germicidal uses are also the wavelengths that are most destructive to human tissue. Thus, these existing systems cannot be used in areas populated by people who are not properly protected from UV radiation. Or when used, their application is limited to relatively small physical areas such as unoccupied rooms, floors, ductwork, doorways, or ceilings or inside of air purifying devices and the like. Since the 1930's the use of germicidal radiation during surgeries has occasionally been practiced, but in these instances all personnel in the area are fully protected from the UV with clothing, skin creams, and UV eye protection which is administratively controlled for the short duration of the surgery. But overall, germicidal radiation systems are not conducive to treating areas in which people are routinely located, thus limiting the major benefits they can provide. Germicidal radiation, with proper protection, can be superior to other forms of sanitation which are used to reduce microorganism populations, such as periodic cleanings with bleach or emitting a toxic chemical mist into the air. But the inability to ensure administratively that everyone in an area is properly protected at all times and for extended periods of time makes the continuous or semi-continuous use of UV decontamination in the presence of persons infeasible. Being able to track persons in an area exposed to germicidal radiation and monitor whether or not they are properly protected from the germicidal radiation as they go about their routine activities would greatly enable this safe and effective disinfection technology to be much more readily deployed in the fight against pathological microorganisms and will help prevent the development of so called antibiotic-resistant “super-bugs.” Continuous electronic monitoring of whether or not persons in the area have adequate skin or eye protection to enable safe exposure to germicidal radiation disinfection is not known in the art.
More recently, other wavelengths of radiation in the visible range have been found to have germicidal activity. High intensity narrow spectrum light (HINS) in the range of 380 to 420 nm, violet light, and particularly the 400-410 nm range centered on 405 nm, has been found to have some germicidal activity. Although these wavelengths are not harmful to humans as is UV radiation, because such high intensities are needed it would not be desirable to expose the unprotected human eyes to HINS, and thus protecting persons within an environment that is being continuously or semi-continuously decontaminated with HINS light is also contemplated in this invention, even though the majority of the discussion centers on the much more studied and practiced decontamination with germicidal radiation. Continuous electronic monitoring of whether or not persons in the area have adequate eye protection to enable safe exposure to HINS light disinfection is not known in the art.